<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<button onclick="alert('请先登陆')">弹出警告框</button>
<button onclick="confirm('确定要删除吗？')">弹出确认框</button>
<script>
    console.log(parseInt(6.1));
    console.log(parseInt(6.9));

    //float
    console.log(parseFloat(6.1));
    console.log(parseFloat(6.9));
    console.log(parseFloat('6.9'));
    //isNaN
    console.log(isNaN(6.1));
</script>
</body>
</html>